How much does a garage conversion cost

Even if you are not planning a full makeover, garage projects have a habit of starting with one simple question. This page breaks it down in plain terms so you can make a confident next move. Before you dive too far in, it can help to glance at the garage door locks landing page so you know what is available if your project involves the door hardware.

Converting a garage into a usable room can be a smart way to add value and space to your home. This guide explains typical UK costs, what affects them, and how to budget effectively.

Converting a garage offers a cost-effective way to gain extra living space, whether it’s for a home office, gym, guest bedroom or utility room. Since the basic structure (walls, roof, floor) is usually already in place, a conversion typically costs less than a full extension. However, costs still vary widely depending on size, condition, services required, finishes and how the garage is connected to the house. This article covers what a garage conversion involves, who it’s for, how it works, real UK cost examples, planning and regulation issues, cost-breakdowns, alternatives, and practical advice for budgeting and managing the project.

By the end you will have a realistic understanding of how much you should budget and what will drive the cost up or down.

What a garage conversion is

A garage conversion involves altering an existing garage structure—detaching the door, infilling or replacing it with a wall and windows or doors, insulating the walls/roof/floor, upgrading services (electricity, heating, plumbing if needed), and finishing the space for use as a habitable room or functional space. Unlike building a new extension on a footprint, you reuse the existing shell which can save money, time and disruption.

Conversions can vary from simple use as storage or utility room to full living space with high specification finishes and bathrooms.

Who a garage conversion is for

Garage conversions are suited to:
• Homeowners short of extra living space but without garden room for an extension.
• Families needing an additional room for children, guests or multigenerational living.
• People working from home who want a dedicated office space.
• Landlords converting a garage in a rental property to create additional habitable rooms.
• DIY-savvy homeowners who want to maximise value and use of their property.
• Anyone wanting to avoid moving house but needing more space.

If your garage is sound structurally, has easy access and you don’t rely on the garage for vehicle storage, conversion is a strong option.

How a garage conversion works

The process for a garage conversion typically includes:

1. Surveying the garage shell for structural soundness, floor slab, roof, walls and damp issues.
2. Planning access from the main house or via its own entry if the garage is detached.
3. Removing or modifying the garage door façade, replacing with wall and windows/doors, or partitioning the space.
4. Insulating walls, roof and floor to meet building regulations for a habitable room (U-values etc).
5. Upgrading the floor—possibly putting in a new floor slab, damp proof membrane or insulation under a finish.
6. Running services: electricity (lighting, sockets), heating, possibly plumbing and drainage if adding a bathroom or utility.
7. Internal finishes: plastering or dry-lining, decorating, flooring, internal doors, skirting and joinery.
8. Compliance: making sure the conversion meets building regulations (fire safety, ventilation, insulation, structural alterations) and possibly planning permission or permitted development status.
9. Final decorations and commissioning of new room.

The complexity depends on whether you are simply converting for living space, or adding wet rooms or kitchen facilities.

Real-world UK cost examples

Here are typical cost examples based on different types of conversion in the UK:

• A single attached or integral garage of about 16 m² converting to a habitable room tends to cost in the region of £10,000 to £20,000. Checkatrade+2Resi+2
• A detached garage or a double garage of around 30-40 m² may cost £20,000 to £30,000 or more, particularly if high specification finishes or structural work is required. The Conversion Guy+1
• For example, one cost guide shows for a single garage conversion typical cost of £10,000–£20,000 for a one-car garage. Checkatrade
• Another source gives a wide range for single garage conversion of £7,000–£20,000 and for double garage £15,000–£55,000 depending on various factors. FMB

These figures are intended as ballparks and individual projects will vary significantly.

Legal, planning and building regulation considerations

When converting a garage you must consider several legal and regulatory factors:

Planning permission

If you are altering the use of the garage (for example from parking to habitable room) or making exterior changes, planning approval may be required. In many cases the conversion falls under permitted development—especially where the structure remains essentially unchanged externally. But if your property is in a conservation area, listed, has restrictions or you add an extension then formal planning permission may be needed. Homebuilding+1

Building Regulations

Regardless of planning, building regulations apply to ensure the new space is safe, structurally sound, suitably insulated, ventilated, fire safe and energy efficient. You’ll need to meet standards for insulation (walls/roof/floor), damp proofing, fire separation (if attached to house or party wall), structural adequacy, new windows/doors, electrical and plumbing installations and egress.

Insulation and damp proofing

Garages are often uninsulated and have no damp proof membrane. Converting to a habitable room means upgrades are needed to meet U-value requirements and to prevent damp or cold.

Structural changes

If you remove or alter load-bearing walls, or significantly change the roof or floor structure, you may require structural engineer input, party wall agreements and additional building control checks.

Utilities

If you add a bathroom or kitchen, you need to connect to water, drainage, gas or electric supply which may trigger further regulation and inspection.

Failing to follow regulations can lead to costly remedial work or insurance issues later.

Cost breakdown: What drives the price

Several factors drive up or down the cost of a garage conversion:

Garage type and size

Integral garages (within the house footprint) are typically cheapest since they already share walls, services and heating from the house. Detached garages cost more because they may require separate servicing, foundations or damp proofing improvements. MyJobQuote+1 Larger floor area means more materials, labour and services.

Structural condition

If the garage floor is below the level of the house, or the slab needs lifting, or the roof structure is poor, costs increase. If you keep the basic structure and minimal work is needed, cost is lower.

Services required

Basic conversion (insulation, plaster, flooring, lighting) is cheaper. Additions like plumbing for a shower/en-suite, underfloor heating, high quality finishes, bespoke joinery or full kitchen raise costs considerably. Resi+1

Finishes and fit-out

The cost difference between a simple finish and high spec can be large. Flooring, lighting, windows, doors, heating, built-in furniture, soundproofing, acoustic insulation all add cost.

Insulation and thermal upgrades

Converting a garage means upgrading insulation of walls, roof and floor and possibly improving the garage door or replacing it with a wall and window(s). These elements add to cost.

Garage door replacement

Often the garage door opening is infilled or replaced with new wall and glazed panels. That work alone may cost £1,000-£3,000 or more depending on size and materials. The Conversion Guy

Location and labour rates

Labour costs vary significantly across the UK. London and the southeast often incur 10-20% higher labour rates than other parts of the country. Rated People

Purpose and complexity

A conversion to a bedroom or living room may cost less than a space with utilities and bathroom. A full subdivision of the garage into two rooms or part-garage/part-room adds cost.

Timing and waste removal

Existing garages often contain stored items which must be cleared. Foundations, damp proof membranes, waste disposal all add to the job’s complexity.

Typical cost ranges for UK garage conversions

Here is a summary of what you might expect to pay:

• Basic conversion (single garage, minimal structural change, simple finishes): £7,000-£12,000 FMB+1
• Average conversion (single garage ~15-20m², good finishes, insulation, basic services): £10,000-£20,000 Checkatrade+1
• Larger conversion (double garage ~30-40m², or detached garage, with higher specification finishes): £20,000-£30,000+ Resi
• Premium conversion (adding en-suite, high end finishes, full utilities): £30,000+ with some examples rising to £40,000-£60,000 in very complex cases. whatcost.co.uk

Remember these figures exclude VAT (if applicable) and depend heavily on the specifics of your project.

Cost example walk-through

Imagine a garage conversion: single attached garage, 18m². You plan to convert to a home office with insulation, heating, new windows, flooring finish, basic lighting/sockets but no bathroom.

• Structural assessment and minor repair: £1,000
• Infilling garage door opening and new window/door: £2,500
• Insulation (walls, roof, floor): £3,000
• Flooring and damp proof membrane: £1,500
• Electrics/heating: £2,000
• Internal finishes (plastering, painting, flooring): £3,000
  Total estimated cost: ~£13,000
  If you add a shower room or high specification joinery the cost might rise by £5,000-£10,000 or more.

Alternatives to full garage conversions

If the full conversion cost is too high you might consider:

• Partial conversion: only part of the garage is converted and the rest used for storage. This reduces costs because less floor area, fewer finishes, fewer changes.
• Minimal fit-out: convert to basic utility or playroom use without full insulation or plumbing, reducing cost.
• Convert part and retain vehicle storage: keep one bay for car and convert the other bay (in double garages) to living space.
• Shelter and storage improvement: rather than full conversion, improve insulation, lighting, flooring for a less ambitious use.

These alternatives allow you to gain value or functionality without full cost.

Tips for keeping your garage conversion cost under control

Here are practical suggestions:

• Clarify scope before work starts; stick to the plan.
• Retain as much of the existing structure as possible (floor slab, walls, roof).
• Avoid major structural changes and large openings unless necessary.
• Use standard sized windows and doors to reduce bespoke costs.
• Choose mid-range finishes; you can upgrade later.
• Get multiple quotes from specialist conversion builders.
• Check whether you need planning permission or building regs and factor those fees in.
• Budget for contingency (10-15%) because hidden costs often emerge (e.g. damp, floor level issues).
• Consider doing simpler items (decoration, flooring) yourself to save labour.
• Make sure your builder provides a detailed breakdown of what is included.

When to call a professional

You should engage a professional builder or architect if:

• The garage requires major structural changes (floor, roof, wall removal).
• You plan to add plumbing or drainage, bathrooms or kitchens.
• The garage is detached and needs full utilities run.
• You are in a conservation area or a listed building.
• You want high end design or bespoke finishes and need detailed build drawings.
  Professionals can help manage compliance, detailed costing, scheduling and quality control.

Conclusion: budgeting for your garage conversion

A garage conversion offers a relatively low-cost way to add value and space, but it still represents a significant investment. For an average single garage you should expect somewhere between £10,000 to £20,000 depending on specification and location. Larger or more complex conversions can go well beyond that. By understanding the factors that affect cost, planning accordingly and getting detailed quotes you can manage the budget confidently. With thoughtful planning your conversion can deliver considerable benefit in terms of extra usable space and increased home value.

Before you move on, it is worth taking a quick look at two closely linked topics. You can also dip into the Garage Door Locks and Handles Help Hub for broader support, then carry on with How Much To Build A Garage and How Much To Build A Double Garage for two useful follow ons.